1. Field of the Invention
The present invention relates to a method for vibration polishing a vehicle wheel.
2. Description of the Related Art
Conventionally, for example, the following techniques are disclosed as a technique of polishing the vehicle wheel.
In the polishing technique disclosed in Japanese Unexamined Patent Publication No. 11-216660, the vehicle wheel attached to a leading end portion of a rotating shaft is inserted in a polishing medium storage tank in which a polishing medium is stored, the rotating shaft is circularly vibrated or vibrated from front to back and from side to side along a plane including a shaft center of the rotating shaft.
In the polishing technique disclosed in Japanese Unexamined Patent Publication No. 2001-353654, the vehicle wheel attached to one end side of the rotating shaft is inserted in a tank in which the polishing medium is stored, while the vehicle wheel is rotated about the shaft center of the rotating shaft, the vehicle wheel is inclined with respect to a horizontal plane and linearly moved.
In the polishing technique disclosed in Japanese Unexamined Patent Publication No. 2003-136394, a workpiece support shaft is rotated about the shaft center while a front face of the vehicle wheel attached to a leading end of the workpiece support shaft faces a flow of the polishing medium that is caused to flow by proper means in the polishing medium storage tank, and a baffle member is placed near a lower portion in a rear surface of the vehicle wheel.
The above-described conventional techniques increase an amount of movement of the polishing medium to an inside surface of the vehicle wheel having a complicated three-dimensional shape. However, the flow of the polishing medium into the inside surface of the vehicle wheel is still insufficiently activated. Particularly a surface pressure of the polishing medium can insufficiently act on a window hole in a disc portion of the vehicle wheel, and burrs of the window hole cannot well be polished. Therefore, it is difficult to evenly polish the whole internal and external surfaces of the vehicle wheel, and it is also difficult to achieve further shortening of a polishing time.